William sawyee



(No Model.) 2 Sheets-Sheet 1.

W. SAWYER. Automatic Safety Switch for Electric Light Circuits. No. 230,346. Patented July 20,1880.

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N.FEYERS, PHOTO LITHOGHAPHFJL WASHINGTON, DJ

(No Model.)

2 Sheets-Sheet 2.

W. SAWYER. Automatic Safety Switch for-Electric L ight Circuits.

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UNITED STATES PATENT @FFICE \VILLIAM SAlVYEI-t, OF NEW YORK, N. Y.

AUTOMATIC SAFETY-SWITCH FOR ELECTRlC-LlGHT CIRCUITS.

SPECIFICATION forming part of Letters Patent No. 230,346, dated July 20, 1880.

Application filed April 27, 1880.

To all whom it may concern:

Be it known that I, \VILLIAM SAWYER, a citizen of the United States, residing at New York, in the county of New York and State of New York, have invented certain new and useful Improvements in Automatic Electric- Light Satety-Switch and Distributing System, (No. 2;) and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which itappertains to make and use the same, reference being had to the accompanying drawings, and to letters or figures of reference marked thereon, which form a part of this specification.

My device relates to means and apparatus for distributing and automatically regulating electric currents to operate electric lamps aml other electric apparatus; and it consists in an glectro-magnet differentially wound aml placed in the main circuit of the electric gen erator. each coil of the magnet having in its circuit an electric lamp; and iti'urthcrconsists in ashunt, which isthrown into the mainline circuit when, through breakage or acci dent, one of the lamps is extinguished or rcn dered inactive or inoperative for the purpose, and thus relieves the intensity of the current passing through tlie remaining lamp.

Heretot'ore, in systems of electric lighting, the electric lamps, have been arranged in ries on the main line, with the main currrent passing through the lamps successively, so that whenever one lamp in the series became inoperative the otherlampswere extinguished on account of the main current being broken when a lamp was broken, and all lights in the series remain extinguished until the circuit was re-established either by replacing the broken'lamp or by connecting thewires outside of the broken lamp.

in my system l overcome these objections by placing each lamp in a branch of themain circuit, the conductingwire of each of said branches being wound diit'erentially and forming the inducingeoils of an clectro-n'iagnet, this electro-magnet being provided with an armature which has a retractile spring connected thereto, the core of the electro-magnet being connected to the main circuit be- (No model.)

fore it enters the lamps, and the lever 01 the armature being connected to the main circuit after said circuit leaves the lamps by a suitable wire and a resistance equal to the resistance in either of the lamps, the main line. circuit passing around the respective coils oi the electromagnet in an oppositedirection, neutralizing each other, thereby causing the electromagnet to remain inactive; but whenever one of the lamps or the branch circuit thereof is broken from any cause the remaining coil now causes the core of the magnet to become energized and attract the armature l; to its pole (the i'acesof the armature aml magnet being provided with platinum or other suitable contactsurihces G) aml make metallic contact therewith, and thereby opening a new route for the current, which is of a resist ance equal to the lampextinguished,amtthus restoring the equilibrium ot' the circuit.

In the accompanying drawings, l igure l is a plan view of my apparatus embodying my invention. Fig. 2 is a diagram illustrating a system of circuits as used in mydevice. Fig. ii is a diagram illustrating a system of lights in a. continuous circuit as in ordinary use.

A is the core of an clectro-magnet differentially wound with insulated coils of wire I J of suitablesize. ()ne terminal ot'each differential coil is connected to a branch wire, I, from the main circuit O. ()ne terminal of coil Jis attached to the main circuit by a wire, J, the main wire 0 being in metallic connection with the core Act" the clectro-magnet by the wire K. The remaining terminals of the coils l. and are connected, respectively, to the lamps L L by conductors l J. The wires 1. J are ieunited after passing through the lamps, and again form the main line 0, amt so on to another scction containing branch circuits with their lamps.

13 is an armature placed opposite to the core of the electro-magnet, and iixed to a lever, (J pivoted at D.

E is a retractile spring, and F a stop limiting the backward movement of lever C. To said lever is connected a wire, P, which contains in its circuit a resistance, H, which is equivalent to that of either of the lampsin the branch circuit, said wire P being connected to the main line 0 after the branch circuits have been reunited after passing through the lamps.

The operation is as follows: The current from the magneto-electric generator or other source of electricity enters the main circuit at O, and is divided at 0 into three branches, I J K, the branch I being connected to one terminal of the coil 1 and branch J being connected with terminal of J, the branch K being in metallic connection with the core of the magnet A, the other terminals of coils I and J being connected to the lamps L I. by wires 1 J. The coils I and J are wound around the core difl'erentially. Thus induction being neutralized, the current will flow through said coils and their conducting-wires to the lamps equally, and after having performed their function are reunited at O and pass off through 0 to the next series of lamps in the system. Now, it' one of the lampssay L -should become broken, the current through coil 1 ceases, while the inductive action of coil J remains and converts the core into a magnet and at tracts armature B and causes the surfaces G to come into contact. A new route for the current has now been opened by wire K, core A, contact-surfaces G, armature B, lever 0, wire I, and resistance H to the main line, one half going through the operative lamp and the other half through resistance H, thus re-establishing the equilibrium between the branches, and the flow of the current remaining uniuterrupted.

I do not limit myself to this mode of ()])('l'- ating the automatic switch or shunt, for it is obvious that the soft-iron core A may be dispensed with, and in lieu thereof I may use a wire, the lateral expansion of which will operate to close the circuit through the circuitpreserving switch. For instance, while the circuit is equally divided through the coil surrounding this wire it remains in its normal condition; but when one of the lamps is extinguished or broken and the current caused to pass through one coil only the said coil will become heated and cause the wire within the coil to elongate and make contact with suitable contact-points in connection with the shunt H, and thus restore the requisite equi librimn, as in the first instance.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is-

1. In an automatic electric-light and distributing system, a differential magnet having a lamp in the circuit of each coil, substantially as described.

2. In an automatic electric-light and distributing system, as described, a system of elecremains inactive until a lamp is broken and thereafter rendered inoperative, when said third branch is thrown into the main circuit and brings into said circuit a resistance equal to the resistance of the lamp extinguished, and thereby restores the normal current passing through the subdivision, substantially as described.

3. In an automatic electric-light and distributing system, the combination of a differentially-wound magnet and a lamp in the circuit of each coil with a shunt around said lamps, whereby upon the breakage of either lamp the magnet is rendered active and the shunt operates to restore the current passing through the remaining lamp to its normal strength, substantially as described.

I. In an automatic electric-light and distributing system, a maindine current divided into three branches, one of which is inactive until one of the others is broken, when the remaining one acts to restore the'circuit which before passed through the broken lamp, whereby the strength of the current passing through this subdivision is restored, substantially as described.

5. In an automatic electric-light and distrilr uting system, as described, the combination of main-line circuit 0, divided circuits I J, and differential coils I J with the lamp-circuit wires I J, substantially as described.

6. I11 an automatic electric-light and distributing system, the combination of main-line circuit 0, divided circuits I J, differential coils I J, and lan'1pcircuits I J with lever 0, provided with a retractile spring and a resistance-coil, H, substantially as described.

7. In an automatic electric-light safely-switch and lighting system, the combination of the core A, branch wire K, forming a branch of the main-line circuit, wires I and J, also form- 

